/*
 * Copyright 2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.social.connect.web;

import org.springframework.social.UserIdSource;
import org.springframework.web.context.request.RequestContextHolder;

/**
 * {@link UserIdSource} implementation that uses the session ID as the user ID.
 * Convenient for applications that don't maintain their own notion of a user.
 * 
 * Relies on {@link RequestContextHolder} for obtaining the session ID. 
 * Will throw an {@link IllegalStateException} if there are no request attributes bound to the current thread.
 * 
 * @author Craig Walls
 */
public class SessionUserIdSource implements UserIdSource {

	@Override
	public String getUserId() {
		return RequestContextHolder.currentRequestAttributes().getSessionId();
	}
	
}
